Using Classic Outlook on Windows for personal email, calendar, and contact management
Same issue for years now here as well.
I've taskkilled outlook in the past to make them go away vs having to constantly close one... click NO, close the next one, click NO over and over and over again.
In my years of using outlook, this is one of the Rage inducing issues that has confounded me for years. Since this is a recent thread on this, I'm posting my two cents.
Please do not prompt me to save changes to any calendar entry that I've opened when there have been no changes after my PC has been locked.